Respiratory apparatuses commonly have the ability to alter the humidity of the breathable gas to reduce drying of the patient's airway and consequent patient discomfort and associated complications. The use of a humidifier placed between the flow generator and the patient mask produces humidified gas that minimizes drying of the nasal mucosa and increases patient airway comfort. In cooler climates, warm air applied generally to the face area in and about the mask may be more comfortable than applying cold air.
Many humidifier types are available, including ones that are integrated with, or configured to be coupled to, the relevant respiratory apparatus. While passive non-heated humidifiers can provide some relief, heated humidifiers generally provide a higher humidity and temperature to the air increasing patient comfort. Heated humidifiers typically comprise a water tub having a capacity to hold several hundred milliliters of water, a heating assembly for heating the water in the tub, a control system to enable the level of humidification to be varied, a gas inlet to receive gas from the flow generator, and a gas outlet adapted to be connected to a patient conduit that delivers the humidified pressurized gas to the patient's mask.
Known heating assemblies may be suitable for its intended purpose, but require complex, costly, and manually intensive manufacturing processes. U.S. Pat. No. 6,660,977 describes an exemplary electrical heating plate structure.